The purpose of this project is to analyze the cellular control of immune function in normal individuals and in certain individuals with neoplastic diseases. We are currently determining the helper and suppressor activity of neoplastic cells from patients with a variety of T-cell lymphomas. We are also currently attempting to develop human (and subhuman primate) monoclonal antibodies directed against human T-cell surface membrane antigens and against the antigens encoded by a retrovirus which is associated with T-cell lymhpomas in certain geographic clusters. Finally, we are analyzing cultured lines of B cells derived from patients with T-cell lymhpomas to determine the isotype preference, susceptibility to normal immunoregulatory influences, and heavy chain switching events in these populations.